Feature request: attrition for "not in any target cohorts"

[ablack3]

Is your feature request related to a problem? Please describe.
In the attrition file I see a large drop with a label indicating they were dropped because of the minEraDuration requirement. This is the first attrition step. However the real reason for the big drop in person and record count is because they have no target cohort record. The treatment cohorts are large because they include all persons in the database. Most of these records are dropped in the first step because they are not in the target cohort, not because of the minEraDuration.

Describe the solution you'd like
A separate attrition log line that indicates number of persons and records dropped because they have no record in any of the target cohorts. This should probably be the first attrition step.

Additional context

[ablack3]

added this in a pr #363 (need to confirm it's correct though)